The present invention relates to a corner member used for forming a foldable box and to a box assembled by using the above corner member.
A box made of wood or synthetic resin assembled in a factory by nailing, screwing or bonding a bottom and a lateral panel together or lateral panels together takes much time and labor in manufacture and is bulky and hence is inconvenient to transport to a place where it will be used or to handle it when it is not in use; thus, it has been proposed to assemble or unfold such a box on location for use.
Examples of such proposed boxes include a box made of synthetic resin having lateral panels which may be raised around a bottom panel through hinge portions (see, for example, Japanese Utility Model Application Laid-Open No. 16295/1980) and another box has been suggested which is designed so that the bottom and lateral panels are separately formed and thereafter joined together (see, for example, Japanese Patent Publication No. 7091/1964). However, as means for joining lateral panels together in an assembly operation, most of them employ such means as nailing, screwing or bonding, thus requiring much time and labor in the assembly and disassembly operations for assembling the box into a developed shape and for breaking down into a transportable configuration. Further, there is a box adapted to be assembled by fitting means using L-shaped connectors (see Japanese Utility Model Publication No. 28676/1977 and U.S. Pat. No. 3,613,931), but since the above connectors are used to join only two faces such as a bottom and lateral panel together or lateral panels together, a large number of such connectors are required and the fitting operation is troublesome. There is still another box which is assembled using hinge-like corner connectors (see, for example, Japanese Utility Model Publication No. 27274/1969), but, in an assembly operation thereof, it is difficult to attach the connectors to lateral panels and the like; thus, a disadvantage arises in that the assembly operation still requires much time and labor. Furthermore, a box may be assembled by engaging means using pins and slots formed on the butt ends of adjacent lateral panels (see, for example, U.S. Pat. Nos. 3,874,546 and 3,446,415), but this box also has disadvantages in that lateral panels are complicated in construction and difficult to produce. Another box which is assembled by fitting means using projections and slots formed on butt ends of adjacent lateral panels (see, for example, U.S. Pat. No. 3,675,808) has a drawback that the strength of the fitting is not sufficient. Further, a box in which ends of butted lateral panels are clamped by corner members and thereby joined together (see, for example, U.S. Pat. No. 3,544,021) is inconvenient in that; since it is necessary to increase the thickness of lateral panels, they can hardly be formed of thin corrugated boards or synthetic resin foam boards.